[Photoshop] Photo retouching - changing background

The requirement is to change photo's background into a solid , light color so that they can enlarge it in the wedding ceremony. (With approval, I'm able to publish the picture of this couple.)

In the original picture:
1. Background is dark, people are standing in back light, which caused the uneven tone on their faces. We need to adjust the tone to make it looks more natural in light background.
2. the bridal dress is merged with background and color's affected. We need to restore it into white color.

Tips:
1 Never rely on just one layer, process separately in different layers for bride's veil, face, hair etc.
2 use masks as many as you want - it makes things much easier to be revised during the work.
3 use channel - find the channel which shows the most contrast to get the veil. copy the selected bridal dress w/veil directly from the channel , you will get a white one, then adjust it in a separated layer to match the color of new background.
4 Be patient. It's a time consuming job.